If its for a single player module, saved or otherwise, there are no variables stored on items unless you are launching it as a server and using server vault PCs. Variables aren't saved onto items in local vault uses.
I did a test which seems to disprove this.
On acquiring an item in SP, I set a local int. Put it down on the ground. Save. Open the save container with NWN Explorer. The area .git file has List > Entry 1 for the item, which has a Var_Table with the Name, Type and Value of the local int.
In game, loading the saved file and picking up the item again, the script recognizes that the variable is already set.
Incidentally, this use of NWN Explorer might satisfy the OP, if the number of items to examine is small.
Remember, we're talking about saving a game, not exporting a character (which might be different).
Perhaps I'm missing something?